GAS STOICHIOMETRY (non-standard conditions)
1. Propane burns according to the following equation:
C3H8 (g) + 5 O2 (g)
à 3 CO2 (g) + 4 H2O (g)
(A) What volume of water vapor measured at 250. oC and 1.00 atm is produced when 3.0 L of
propane are burned at STP?

(B) What volume of oxygen at 20. oC and 102.6 kPa is used if 640. L of CO2 is produced?  The
CO2 is also measured at 20. oC and 102.6 kPa .

(C) If 465 mL of oxygen at STP are used in the reaction, what volume of CO2, measured at
37 oC and 0.973 atm, is produced?

(D) When 2.50 L of C3H8 burns at STP, what total volume of gaseous products is formed?  The
volume of the products is measured at 175 oC and 1.14 atm.

2. Carbon monoxide will burn in air to produce CO2 according to the following equation:
2 CO (g) + O2 (g)
à 2 CO2 (g)
What volume of oxygen at STP will be needed to react with 3500. L of CO measured at
20. oC and a pressure of 0.953 atm?

3. Silicon tetrafluoride gas can be produced by the action of HF on silica according to the
following equation:                 SiO2 (s) + O2 (g)
à SiF4 (g) + 2 H2O (l)

1.00 L of HF gas under pressure at 3.48 atm and a temperature of 25 oC reacts
completely with SiO2 to form SiF4.  What volume of SiF4, measured at 15 oC and 0.940 atm,
is produced by this reaction?

4. One method used in the 18th century to generate hydrogen was to pass steam through red-
hot steel tubes.  The following reaction takes place:
3 Fe (s) + 4 H2O (g)
à Fe3O4 (s) + 4 H2 (g)
(A) What volume of hydrogen at STP can be produced by the reaction of 6.28 g of iron?

(B) What mass of iron will react with 500. L of steam at 250. oC and 1.00 atm of pressure?

(C) If 285 g of Fe3O4 are formed, what volume of hydrogen, measured at 20. oC and 1.06 atm,
is produced?

5.  Sodium reacts vigorously with water to produce hydrogen and sodium hydroxide according
to the following equation:       2 Na (s) + 2 H2O (l)
à 2 NaOH (aq) + H2 (g)

If 0.027 g of sodium reacts with excess water, what volume of hydrogen at STP is formed?

6. A 2.55 grams sample of ammonium nitrite (NH4NO2) is heated in a test tube.  The
ammonium nitrite is expected to decompose according to the equation:
NH4NO2 (s)
à  N2 (g)  +  H2O (l)
If it does decompose in this way, what volume of N2 will be collected?  The water and gas
temperature are 26 oC, and the barometric pressure is 0.98 atm.

7. A 1.60 gram sample of KClO3 is heated to produce O2 according to the following unbalanced
equation:        KClO3 (s)
à  KCl (s) +  O2 (g)
Assume complete decomposition.  What volume of O2 is collected at 23 oC and 1.9 atm
pressure?

*8. A 2.16 gram sample of Pb(NO3)2 is heated in an evacuated cylinder with a volume of
1.18 L.  What is the total pressure in the cylinder after decomposition and cooling to a final
temperature of 30. oC?
Pb(NO3)2 (s)
à  PbO (s) + NO2 (g) + O2 (g)

Answers:  1.) (A) 23 L        (B) 1070 L        (C) 326 mL        (D) 25.2 L
2.)
1550 L        3.) 894 mL        4.) (A) 3.35 L        (B) 489 g        (C) 112 L
5.)
13 mL        6.) 1.0 L        7.) 0.25 L        8.) bonus problem!

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